Warp switch



Nov. 26, 1957 J. E. WILDER 2,814,686

WARP SWITCH Filed Sept. 24. 1956 W 29 II PI .P

INVENTOR. JUSTIN E. WILDER @M Q UM A TTORNE Y United States atent WARP SWITCH Justin E. Wilder, Goshen, Ind., assignor to Penn Controls Incorporated, Goshen, Ind., a corporation of Indiana Application September 24, 1956, Serial No. 611,439

Claims. (Cl. 200-67) The present invention relates generally to electrothermally operated switches or specifically to such switches having multiple contacts which must sequentially open or close when the switch is actuated.

In switches of this type it is customary to form a switch in stacked arrangement with each of the contacts carried on an extending flexible blade, the blades being separated by appropriate insulating spacers. When the switch operating sequence required that one pair of contacts close before a second pair of contacts should open, it has been customary to form the first to close pair of contacts each on flexible blades, the switch actuating motion then serving to first close the last mentioned pair of contacts, with continued flexure of both blades then serving to open the next-to-open pair of contacts. This construction requires that both contacts of the first-toclose pair of contacts be mounted on flexible blades. The uniformity of operation of a series of switches assembled according to the construction referred to above thus depends on maintaining uniform the direction of extension of both flexible blades in each assembled switch. This construction also made proper operation of the switch dependent on the uniformity of the height of the stacked members between the two flexible blades. This problem is accentuated by the difficulty in holding proper flatness tolerance on relatively thin flexible blades.

In the construction of the present invention this difficulty is obviated by so forming the switch that none of the sequentially operated pairs of contacts are both mounted on flexible blades. Each of the sequentially operated switches is composed of one rigid blade and one flexible blade. Further, the present invention embodies a construction in which, upon actuation of the switch, a first pair of contacts are closed then a second pair of normally closed contacts are opened with a snap action and by means of a link extending therebetween a third pair of normally closed contacts are opened; the opening of the last mentioned pair of contacts occurring at some point within the travel of the snap acting mechanism which opens the second pair of contacts.

The object of the present invention is to provide a sequentially operating switch in which each of the pairs of switch contacts are dependent for proper operation upon the maintaining the desired extensional direction of only one flexible blade.

A further object is to provide a sequentially operated switch having first and second normally closed pairs of contacts in which the last-to-open pair of contacts can be operated anywhere within the travel of the flexible blade carrying the movable contact of the first-to-open of the normally closed pair of contacts, thereby making proper operation of the switch independent of minor variations in the height of the switch stacking elements.

A further object is to provide a warp switch having a bimetal actuator which moves an operating member to first close a normally open pair of contacts, then snap open a normally closed second pair of contacts and finally open a normally closed third pair of contacts.

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Other objects will become apparent as the description proceeds.

To the accomplishment of the above and related objects the invention may be embodied in the forms illustrated, in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that specific changes may be made in the construction illustrated and described so long as the scope of the appended claims is not violated.

Figure 1 represents a side view of the switch assembly with the contacts in deactuated position.

Figure 2 is a view similar to Figure 1 but showing the contacts in actuated position.

Referring first to Figure 1, there is shown at 10 a stack mounting bracket having a forwardly extending upper flange 11, a forwardly extending lower flange 12 and a rearwardly extending side flange 13. Flange 13 may be used for suitably mounting the switch assembly and flange 12 serves to fixedly carry a bimetal ambient temperature compensating blade 14. Rigidly mounted on the free end of blade 14 is an oifset bracket 16 which rigidly carries on its upper end a bimetal actuating blade 17. An electric heating coil 18 suitably embraces a portion of bimetal blade 17. A stud 19, having its upper end threaded, extends freely through an appropriate opening in the free end of blade 17. The threaded end of the stud 19 is threaded through an appropriate opening in the lower end of an operating member 21. The upper end of member 21 extends freely through an opening in a rigid stop member 22. As may best be seen in Figure 1, the extreme end of member 22 cooperates with a forwardly extending tab 23, formed at the upper end of member 21, to limit downward motion of the member 21. The upper portion of member 21 is reduced in width to provide a shoulder at 24 which, as may best be seen in Figure 2, cooperates with the end of the member 22 to limit the upward motion of the member 21. Member 21 also carries fixedly attached thereto an abutment member 26 of generally cylindrical shape.

The upper flange 11 of the bracket 10 has stacked thereon suitable insulating members 27 and terminal members 28 which permit electrical connection to the heater 18, the upper one of the two terminal members 28 also serving as an electrical connecting terminal for a flexible blade 29. The free end of flexible blade 29 which has an inherent upward bias cooperates with abutment member 26 and carries the movable contact 31 of a normally opened pair of contacts 31, 32. A flexible blade 33 extends through the stack assembly to provide a wiring terminal and adjacent its free end which has an inherent upward bias, carries the movable contact 34 of a normally closed pair of contacts 3435. Overlying the blade 33 and separated from it by an insulating spacer is a rigid bar 36 which extends through the stack assembly to provide a wiring terminal and at its other end carries the fixed contacts 35 and 32. Overlying the bar 36 is a rigid stop element 37. Overlying the stop element 37 is a flexible blade 38 which carries at its free end the movable contact 39 of a normally closed pair of contacts 39-41. A snap action operator 42, carrying a compression spring 43, cooperates with the extending end of the blade 38 serving to snap blade 38, and consequently contact 39, downwardly when the member 42 is moved over center with relation to the blade 38. An extension member 44, formed of suitable insulation extends through an appropriate slot in the operating member 21 thereby forming a two-way connection for transmitting either upward or downward motion from member 21 to member 44.

A link or thrust member 45 has reduced portions at each of its ends forming shoulders 45a and 45b. As may best be seen in Figure 2, the reduced portion forming the shoulder 45b is of suflicient length to contact the blade 33, forcing open the contacts 34-35, when the shoulder 45b comes to rest against the bar 36. The shoulder 4511 on the member 45 cooperates with the end of blade 35 to provide for the aforementioned opening of contacts 34-35 at a point within the travel of blade 38.

A rigid bar 46 carries at its outer end the fixed contact 41. Insulating spacers 27 separate the bar 4b from the stop member 22 which has overlying it a cap member 47. The stacked assembly just described is clamped together on the flange ill by means of screws 48 which ex- .L

tend through the stack and are threaded into the flange 11.

Operation With the switch assembly in the de-actuated position, as shown in Figure 1, the bimetal actuator 17 is in generally horizontal position as is also the ambient compensating bimctal 14. It will be understood that the position of the outer end of the bimetal actuator 17 will be independent of the ambient temperature because of the compensating action of the bimetal blade 14 whose movement in response to increased temperature is opposite to that of bimetal actuator 17. In this de-actuated position of the actuator 17 the operating member 21 is positioned so that contacts 41-39 are closed, as also are contacts 34-35, and the abutment 26 holds the contacts 31-32 open. When the heater 18 is energized, the bi metal actuator 17 begins to warp upwardly, at its outer end, toward the position shown in Figure 2. The resulting upward movement of the operating member 21 first permits the abutment 26 to leave the flexible blade 29 permitting contacts 3132 to close. Continued upward movement of the operating member 21 carries the spring 43 through center resulting in the snap opening of the contacts 39-41. Intermediate the consequent downward travel of the flexible blade 38, shoulder 45a on the member 45 is struck by blade 38 forcing the member 45 sharply downward opening the contacts 34-35. It will be apparent that as the bimetal actuator moves toward the position of Figure 2, contacts 31l32 are first closed, then contacts 39-41 are opened, and subsequent to the initial opening movement of contact 39, the contacts 3435 are opened.

It will be noted that none of the switches are dependent for their proper operation upon holding uniform the direction of extension of more than one flexible blade. Further, since proper operation of contact pair 3435 can occur anywhere within the travel of flexible blade 38, closely held tolerance on the length of the member 45 and the stack height between the flexible blades 33 and 38 are unnecessary. The present invention thus provides a sequentially operated warp switch in which the contacts are operated in a predetermined sequence but which is relatively well suited to mass production because the holding of close tolerances on the switch assembly components is unnecessary.

It will be understood that the invention herein de scribed may be modified over that disclosed; the invention is to be limited only as defined in the following claims.

What is claimed is:

1. A thermally operated multiple contact switch assembly of the stacked type having a normally open pair of contacts which must be closed prior to the opening of a plurality of normally closed pairs of contacts, one pair of said normally closed contacts being snap acting, said switch assembly comprising a switch operating member. a rigid blade and a flexible blade for mounting each of said pairs of contacts, each of said rigid and flexible blades carrying respectively the fixed and movable contacts of its corresponding pair of contacts, a thermally operated actuator adapted when energized to move said switch operating member in switch-operating direction, an abutment carried by said operating member adapted to cooperate with the flexible blade of said normally closed pair of contacts, a two-way connection between said operating member and said snap acting pair of normally til) closed contacts, said abutment and said two-way connection being so spaced on said operating member that as said operating member moves in switch-operating direction said abutment first permits said normally open contacts to close and then opens said normally closed snap acting contacts, and a link member extending between the flexible blade of said normally closed snap acting contacts and the flexible blade of said other normally closed pair of contacts adapted to open said last mentioned pair of contacts at a point within the opening travel of the flexible blade of said normally closed snap acting contacts.

2. A thermally operated multiple contact switch assembly of the stacked type having a normally open pair of contacts which must be closed prior to the opening of a plurality of normally closed pairs of contacts, one pair of said normally closed contacts being snap acting, said switch assembly comprising a switch operating member, a rigid blade and a flexible blade for mounting each of said pairs of contacts, each of said rigid and flexible blades carrying respectively the fixed and movable contacts of its corresponding pair of contacts, an over-center switch actuating member cooperating with the flexible blade of: said snap acting contact pair to operate said last mentioned contact pair with a snap action, a thermally operated actuator adapted when energized to move said switch operating member in switch-operating direction, an abutment carried by said operating member adapted to cooperate with the flexible blade of said normally closed pair of contacts, a two-way connection between said operating member and said over-center switch actuating memher, said abutment and said two way connection being so spaced on said operating member that as said operating member moves in switch operating direction said abutment first permits said normally open contacts to close and then opens said normally closed snap acting contacts. and a thrust member extending between the flexible blade of said normally closed snap acting contacts and the flexible blade of said other normally closed pair of contacts, said thrust member being adapted to open said last mentioned pair of contacts at any point within the opening travel of the flexible blade of said normally closed snap acting contacts.

3. A thermally operated warp switch assembly of the multiple contact type having a normally open pair of contacts which must be closed prior to the opening of a plu rality of normally closed pairs of contacts, one pair of. said normally closed contacts being snap acting, said switch assembly comprising a switch operating member. a rigid blade and a flexible blade for mounting each of said pairs of contacts, each of said rigid and flexible blades carrying respectively the fixed and movable contacts of its corresponding pair of contacts, an over-center switch actuating member cooperating with the flexible blade 0! said snap-acting contact pair to operate said last mentioned contact pair with a snap action, a bimetal warp element actuator adapted when energized to move said switch operating member in switch-operating direction. an abutment carried by said operating member adapted to cooperate with the flexible blade of said normally closed pair of contacts, a two-way connection between said operating member and said over center switch actuating member, said abutment and said two-way connection being so spaced on said operating member that said operating member moves in switch operating direc tion said abutment first permits said normally open con tacts to close and then opens said normally closed snap acting contacts, and a thrust member extending between the flexible blade of said normally closed snap acting contacts and the flexible blade of said other normally closed pair of contacts, said thrust member being adapted to open said last mentioned pair of contacts at a point within the opening travel of the flexible blade of said normally closed snap acting contacts.

4. A thermally operated warp switch assembly of the multiple contact type having a normally open pair of contacts which must be closed prior to the opening of a plurality of normally closed pairs of contacts, one pair of said normally closed contacts being snap acting, said switch assembly comprising a switch operating member, a rigid blade and a flexible blade for mounting each of said pairs of contacts, each of said rigid and flexible blades carrying respectively the fixed and movable contacts of its corresponding pair of contacts, an over-center switch actuating member cooperating with the flexible blade of said snap acting contact pair to operate said last mentioned contact pair with a snap action, a bimetal warp element actuator adapted when energized to move said switch operating member in switch-operating direction, an abutment carried by said operating member adapted to cooperate with the flexible blade of said normally closed pair of contacts, a connection between said operating member and the free end of said over-center switch actuating member, said abutment and said connection being so spaced on said operating member that as said operating member moves in switch operating direction said abutment first permits said normally open contacts to close and then opens said normally closed snap acting contacts, and a thrust member extending between the flexible blade of said normally closed snap acting contacts and the flexible blade of said other normally prising a switch operating member, a rigid blade and a flexible blade for mounting each of said pairs of contacts, each of said rigid and flexible blades carrying respectively the fixed and movable contacts of its corresponding pair of contacts, an over-center switch actuating member cooperating with the flexible blade of said snap acting contact pair to operate said last mentioned contact pair with a snap action, a condition responsive actuator adapted to move said switch operating member in switch-operating direction, an abutment carried by said operating member adapted to cooperate with the flexible blade of said first pair of contacts, a connection between said operating member and the free end of said over-center switch actuating member, said abutment and said connection being so spaced on said operating member that as said operating member moves in switch operating direction said abutment first permits said first pair of contacts to be operated and then operates said snap acting contacts, and a thrust member extending between the flexible blade of said snap acting contacts and the flexible blade of another pair of said further pairs of contacts, said thrust member being adapted to operate said last mentioned pair of contact at any point within the travel of the flexible blade of said snap acting contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,436,909 Werner Mar. 2, 1948 2,446,307 Shaw Aug 3, 1948 2,498,127 Kuhn Feb. 21, 1950 2,568,323 Dales Sept. 18, 1951 2,641,668 Larocco June 9, 1953 2,774,836 Powers Dec. 18, 1956 FOREIGN PATENTS 410,794 Germany Mar. 18, 1925 

